Fucose binding lectin from Lotus tetragonolubus seeds binds to human granulocytes and stimulates a chemotactic response. Analysis of binding by flow cytometry shows that this lectin binds avidly to neutrophils, quantitatively less to monocytes, and not at all to lymphocytes. Studies will be conducted to determine the nature of the cell receptor and how binding to the receptor effects neutrophil and monocyte function. Additional studies using I125 labeled FBL will be performed to determine the number and heterogeneity of FBL receptors on human myeloid cells. This lectin will also be used as a marker to analyze human leukemias to determine if it will differentiate myeloid and lymphoid leukemias as well as granulocytes and myelocytic leukemias.